Healthcare associated infections (HAIs) are a leading cause of death in the United States, despite being largely preventable. HAIs can be significantly reduced through the use of guideline-based infection prevention processes, e.g., aseptic technique during the placement of invasive devices and hand hygiene during patient care. In the emergency department (ED) care setting, millions of invasive devices are placed each year and numerous opportunities for hand hygiene exist. In recent years, HAI prevention in the ED has become more paramount given the growing problem of ED crowding. ED crowding is a major patient safety concern associated with significant mortality and poor care quality. During times of ED crowding, patients' needs are often met with insufficient resources. Patients commonly receive care from understaffed healthcare providers in cramped, unsafe settings, which likely affect guideline-based care. However, no study has examined infection prevention in the context of ED crowding. Guided by Donabedian's framework of healthcare quality, this study aims to determine the relationship between ED crowding and patients' receipt of guideline-based infection prevention processes, i.e., aseptic technique during urinary catheter, peripheral venous catheter, and central venous catheter placement, and hand hygiene during care. The proposed study will be conducted in the ED of an urban, tertiary hospital in northern Manhattan. Direct observations of infection prevention processes will be representative of all shifts and days of the week. Processes data will be recorded on psychometrically sound checklists, which reflect current evidence- based guidelines. Checklists include those developed by the World Health Organization and adapted from hospital policies. Observers will undergo rigorous testing throughout the course of the study to ensure high levels of inter-rater reliability (kappa >0.9). More than 900 observation periods will be included in analyses. Checklist data will be aggregated during each observation period and an adherence score will be calculated. Adherence scores will be the main variable of interest. ED crowding will be the primary predictor variable and will be measured using a validated, standardized instrument at the start of each observation period. Depending on the distribution and spread of data, a multivariate linear or logistic regression model will be used to analyze the relationship between ED crowding and patients' receipt of guideline-based infection prevention care. The short term goal of this study is to demonstrate the need for improved infection prevention in the ED, with the ultimate goal of facilitating interventions that improve evidence-based practices and prevent HAI. As such, this study is well aligned with the National Institute of Nursing Research's goal of disease prevention. Further, the receipt of this award will attest to NINR's mission to train the future generation of nurse scientists. The applicant is a BSN to PhD student eager to become a nurse scientist and improve care quality in the ED.